Tunneling-shield.



No. 794,579. PATENTED JULY 11, 1905.

Y E. D. WRIGHT.

TUNNBLING $HIELD. APPLICATION nun APB.10,1905.

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No. 794.579. PATENTED JULY 11, 1905. E. D. WRIGHT.

TUNNELING SHIELD.

APPLIOATION FILED APR.10.1905.

2 SHEBTS-SHEET 2 ATTORNEYS NITED STATES Patented July 11, 1905.

PATENT OFFICE.

TUNNELlNG-SHIELD.

SPECIFICATION forming part of Letters Patent No. 794,579, dated July 11, 1905.

Application filed April 10, 1905. Serial No. 254,849.

To all whom it may concern:

Be it known that I, EDWARD DELAFIELD WRIGHT, a citizen of the United States of America, residing in Sewaren, county of Middlesex, State of New Jersey, have invented certain new and useful Improvements in Tunneling-Shields, of which the following is a specification.

My invention relates to apparatus for the construction of tunnels, especially such as are intended to be carried through water-bearing strata and in which an advancing shield is employed as the excavation is advanced and the tunnel-lining is put in back of the shield, the operations being carried on under an air-pressure greater than atmospheric pressure.

The object of my invention is to provide efficient means to prevent inrush of water or an escape of air between the iron tunnel-lining and the tail end of the shield.

In the accompanying drawings, Figure l is a diagram, on a small scale, indicating a tunnel end and shield. Fig. 2 is an enlarged longitudinal section through a part of the tail end of the shield and the forward segments of the tunnel-lining when provided with my improvement, and Fig. 3 is a plan view of the strap-drawing means.

Referring to Fig. l. A represents the shield, which has the usual forward cutting edge a and air-locks B B. The tunnel-lining, which preferably is built up of curved segments, is represented at G, the tail end of the shield being outside of and surrounding the forward end of the tunnel-lining. Hydraulic jacks D D are mounted on the shield in such positions that their piston-heads d may be brought to bear against the advanced side of the last-introduced ring of tunnel-segments to force the shield forward at the proper time, as is well understood in this art.

compressed air. To meet this difficultylbevel the extreme outer end of the tail end a of the shield, and I apply at that point a filling-ring R of Wedge section, this filling-ring being preferably built up of segments. Connected with each segment of the ring is a steel strap S, extending forward between the tail end of the shield and the lining to a point in advance of the lining, where it is provided with spring means to tend to draw the wedge ring R tightly to the joint. In the present instance I have shown secured to the end of the strap S, in advance of the lining, a rod 5 with nuts and a collar 8 on the outer end to bear against the rear of a spiral spring P within a cylinder 12, secured to the inner face of the shield by a strap 10, Fig. 3, or other suitable means.

I claim as my invention In combination with a tunnel-lining and its advancing shield, having its tail end beveled, a packing-ring of wedge section to close the joint and spring means to draw the ring to its seat.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

-E. DELAFIELD WRIGHT.

Witnesses:

THos. A. STODDART, D. I B. MARSHALL. 

